Blade sharpening machine



Sept. .6, 1932.

w. EL mcKERsoN BLADE SHARPENING uAcHIn-E 6 Sheets-Sheet 1 Filed Aug. 24,1927 vive? 7?.

Z'M'ckerjom MM mqy W. E. NlKER$ON BLADE SHARPENING ummm 'Filed Aug. 24,1927 6 Sheets-Sheet 2 l sept. s, 19amA @sept 6, 19324 w. E. NlcKr-:RSON

' BLADE SHARPENING MACHINE 6 Sheets-Shet 4 Filed Aug. 24, 1927 W. E.NICKERSCN ,BLADE SHARPENING UACHINE Sept. s, 1932.

` Filed Aug. 24. 1927 6 SheetsnShget 5 Sept. 6, 1932.

w. E. NlcKl-:RsoN

BLADE SHARPENING IACHINE med Aug. 24. 1927 e sheets-snm s nvenr.VVLZZzQWzEJViCePSQn l Patented Sept. 6, 1932y UNITED srTEs PATENTlOFFICE WILLIAM ZEKER!" NICKERSQKQF BOSTUN, MASSCHSETTS, SSIGNOR TOGILLETTE SAFETY RAZOR COIPANYQF BOSNIE ISSQHUSETTS, A CORPORATIDN GFDELA- 'WARE sxmsnmo miennes Murmel-'inea um ai., m7. semi No. nasse.

This invention relates to blade-sharpening machines, and morelparticularly to ma chines for sharpening blades having curved edges. Theobject of the invention is to provide a machine which.willfautomatically sharpen such blades with accuracy and uni formity,and which will be capable of such adjustments as will adapt it toproducethe curvature desired in any given blade edge, the

thickness of the blade, and thefangle, width` and concat-ity ofV theedge bevel.

The features in which my invention reside are hereinafter described inconnection with the accompanying drawings, insvliichw Fig. 1 is a. planview of the machine; Fig. 2 is a vertical section en .the line 2--2 inFis. 1; i

Fig. 3 is a section on the line, 7,.-3 in Fig.. 1; Fig. 4 isa plan viewillustrating one ad C justed relation of the bladeholjding parts to hharpening i l Fi g. 5 is a similar view showungthe bladeA the abradingwheel during t operation;

holding parts in loading and u tinus Fig. 6 is a detail viewillustratingthe son struction of the blade supports.4

. Fig. 7 is a, detail view in sectie `Q on the line 77 in Fig. 4;

Fig. 8 is a section on the line 8--8 in Fig. 1; Fig. 9 is an elevationof the blade-supportl ingy unit as viewed from the front ofthe mm chine;Y

Fig, 10 is a detail view, in section, of'a 'part ofthe unit shown inyFig. 9; i v

Fig. 11 is a horizontal section taken online :l1-1l in Fig. 3 and Fig.12 is a plan view of a. blade on.l which the machine is adaptedr tooperate.

Figs. 3&12 inclusive are drawn to a larger scale than the remainingfigures.

In general, the machine illustrated in cludes a blade-carrying unit and'an abr'adng unit which are conveniently supported by individual basepiecesr bolted to a general base plate A, to which also are securedcertain other parts employed forproducing variousy ment in apredetermined path between the blade and the sharpening means, theformer being acted upon during such oscillatory movement by an abradingelement included in the sharpening means. Said element preferablyconsists of a rotating disk of which the angular position of the axisrelative to the portion of the edge bei-ng sharpened remains constantduring the period of contact between said disk and the blade, andprovision is made formoving the blade into a convenient loading andunloading position after it. has been operated upon by the abradir-.gdisk. The parts are so constructed that such adjustments ma be made aswill enable the machine to pro uce aecuratelyfformed edges of anydesired curvature and bevel contour within the limits of adjustment.1

The parts constituting the bladeholding unit in the machine .illustratedinclude a base piece B 'carrying a fixed vertical spindle B1 .havingjournaled thereon a sleeve B2 which may have a ball-bearingB interposedbetween its lower end and the top ofthe base after described. A bladeclamp is secured to the top of another sleeve B4 rotatable about thesame axisas the sleeve B2 and here shown as j'oural'ed on the spindle B1and resting on-- the upper end ofthe sleeve B2. The sleeve B4 isindependent ofsleeve B2 in its movements except as later described,thereby pro vi'dng for the movement of the hladeclamp into loading andunloading position, but during the sharpening operation these twosleeves are caused to oscillate in unison by means of a coi-led springB5 surrounding the sleeve B2 and secured at its ends to the two sleevesrespectively, this sprin being underk sulli'cient tension normally tolqiold a stop B6 on the sleeve B4 firmlyy against another stop B7 on thesleeve B2 during the oscillations of the latter sleeve. The stop B6 onthe sleeve B4 is shown as a solid stop, Figs. 2 and 9, and tire stop B7on. the sleeve B2 may consist of a bolt horizontally and' adjustablymounted .in a bracket B8 secured tothe sleeve B2.

The blade clamp, of which the details are showny in Figs. 4, 5, 6 and Zincludes horizontal topl and bottom plates B9 and B10 respectively. Theplate B10 is preferably made -piece BY," the sleeve B2 being oscillatedas herei sharpening device during the oscillation of the;sleevesaisjysodetermined that.` 'the l point of A,thegblade travels ijust tothea'brading:` dej vice on yeach oscillation.

The upper clamping plate B^9 .may be;

pivoted toV a block B-13 bolted tothe rear beingi surrounded by a coiledspring B-lwhic i I y r y 7 every 'sii'cli"movement"nis"` permitted. Atits' 'frontedgiethe 'tipp'erclamp plate B-k-9 has anoutline-fSiniiiftftime ef the blades to: be,

operated upon, 'as shown ink Fig. 4,; and lo ver`. lies a'plateBf-Llion'which the rbladesrest. duringthcsliarpcningfopcration,the late 134-16' being detachably; secured to the, ront portionofthefbottom' plate, Bl() and being provided with :si'iitSable]inea-nsfor positioning the blade such asjthe'pins B-l'shown in'y Fig'.4."'Thecontourof the upper clamp platel B9and` thelocati'on of thepositioning pins B`117A sh'own'fiii 4 are suitable for use .wahl-thevSpfeeiin.forni of blad@V Bla-:issues- I Y. lifted with v For p forcinglvthe: upper clampplate B9 y carried by the Standard C2, includes arotary .bd` ik during thesharpening operation,l I em loy a ra mg dis D"w'lch'may be madeof any a plunger-i0 movable vertically in the ront;`

trate'd in llin'ggflQ whic providedfw'ith af straight back e de;

oration B-19fan`dpsh y 'rhelbiadeisfposieioneioniire plate Basie typlacing its back (Viutermost ,j-PlIlS, B-rl'fald Pi'lSS'lIg Lill"lltemedmt P1117@ chine), and 'a driving and timing mechanism which'controls the operation `of the cam VATdriiimaccordingtocycle ofoperations of the :machine with which it is used- A In the present casethe'cams employed will have suchshapes and will be so-located withreference f, i l v t nto one another Aasto operatethe various arts-janotherv having positioningl pins :differently splacedandjlocatedthereonto adapt the' inal` ihrtugif'ihe permise@ islieiininstitue, Fig. @andas rigiai-'yiieidinthis posata dur;

ing the sharpening; operation I'neans fof,

ldowirwartyl'on'it asi ve re'iiiafterdescribed.` The plate 13e-16 canberetrieved 'and replaced'by ine to 'shrpnvzblades of varioussizes andwshapesr' jAt itslfront -e'dgeon 'the under side the clamp i plate5B"-;%'9" is' preferably provided springBf-QO located in aYrecessvformedpi eclampplate and serving to hold:theblade:uponj 'theplate B'"1'6 during f vthe first partfftheupward movement of the ,50

late B-9, f thereby preventing the blade rom adhering to'thela'ter:plate and/being downwardand'causing it lto grip the blade end of abacket'C secured to a standard C2, which'ais carried by the general baseplate at the "rear cfthemachine. The axiso' the plunger 'C is coincidentwith ythe axis of` the spindle B1 and' when the plunger is forceddownward', vits smoothly finished vlower end" bears on 'the' top of'a'sinooth stud B231v se cured' to vthe u per clamp plate B9 and pro#)ecting upwar therefrom, thus enabling the d in thetopuofthe sleeve. 6i`By this 'adjustmeiit' tothe upper end of the plunger C by means," oiga'link C4. "Ne'ar'its rear endtlie lever C3" is"v connected'tothe"standa-r'd(52by a 'coiled spring C5 tending to lift the plunger@fthe i-plunger'being forced downward by means of a rodQ connected atits lower end to the reirendof the'lever C3 and at its upper end to asuitable operatingniechanism which l will be liereinafterreferred to astthe .over- ,head mechanism.` The guide pin lCfrpros ported on jec'tingfrom "the plunger Cinto .avertical i enc'y of the plunger to. turn `onaccountof the frijctional1 y drag y exerted .on it ,by the oscillat-l inblade carriert at ltheir fpoint ofcontaca slot C8 in the bracket C',overcomes any .tend-i l v yhelovefrhead mechanismdis tliagrammat-`ically illustrated in Fig. 2, by the cam drum K-Q levers K-\22, andpressure controlling valve casing K-i-28 and maybe constructedin''accordan'ce with. the voverhead mechanism shown and. described in myprior Patent No. 1,235,590, dated August 7th,',1917, in which`Figs.1i,f19Eaiid 20 illustrate the mechanism Yfinqu'e'stio'n; "Brieflydescribed, thi's mechanism` includes a rotary drum carrying a numofythemachinev according ytofthe cycle ere- Aberief cams, each ofrwhich servesto lift a pull ,rod (such asl 'the ,rod C6`in thepresent vmavinafter'ldescribed. It will be observed on reference to Fi 1:8` of myprior'patent that each of the pnl ods 'has a spring interposedbetween-it and-the cam-operated lever which lifts it, and lthe vsamearrangement is ein- 'ployed in connection with thesprescnt inachine, sothat after any ull rod such as C6 lhas completed itsu'pwa'i movement thecoi'- res'ponding spring willprovide fora certain p amount ofdost motionin the operating cam,

The abrading unit, the parts of which are stropping 'as'desired,mechanism for rotating justingjti in various' ways with reference to icavity of t'lie'bevcl. "In designing'the abrad-l tween the ,blade and'the abrading disk Dls taken as a reference point and is 'assumed shaftD4 by iexible driving means, as the belt D-5, the countershaft D-4 beingjournalled in blocks D-6 located near the rear of the machine andcarried by a support D-7, Figs. 3 and 8. Between the bearing D-8 and thesupport D-7 is interposed an arm D-8 which has the bearing D-B at itsforward end, and is p ivotally connected at its rear end to the supportlD--7v by providing` it with threaded pivot pins D-9 having pointsextendin into lugs D`10 carried by the support D in such manner as toenable l the disk D to be raised and lowered inits plane sufficiently tomove it out `of or into contact with the blade B-18. The abrading actionof the disk in a downward directionmay be Vlimited b means ot'v a stopscrew D-1l, Fig.. 3,.whic is preferably made adjustable vertically bythreading it into thearm D-8, the screw` D-ll resting atitslower end'ona bearingplate D-12 mounted on a vcarriage D13, which also serves'indirectly to carry the support D-7, the vertical position of thecarnage.

D-13 with reference to the base Abeing xed. The upper end of the stopscrew' D-ll is .preferably provided with a head D--14 by means of whichit may be turned and which may have thereon 'a graduated scaleD-15, Fig.1, the adjustment of the stop screw D--ll being'indicated by theposition of this scalewith reference to a suit-l able index such as theupstanding ost D-16 fixed in the arm D-8 as shown in i 3,Vv `A spring,D--17 may also be secure to the arm D-l-.8 and provided at its upper endwith a projection D--18 adapted to enter any one of a number of shallownotches D-119 formed on the outer ed e of the head -D-14, thus serving,-to hol the screw D-11 against accidental .displacement afteradjustment. By meansl of this stop screw the extent of the abradingaction may be so limited that in grinding, for example, only the upperhalf of the blade will be acted'upon.

That side of the support' D-7 which is remote from the belt D--5 isprovided with bearing portions, wherebyk the support is pivotallymounted on a pintle D--20, carried by two upwardly and laterallydirectedarms D--21 in turn carried by a block D-22, the pintle D--QObeing so positioned that its axis, if prolonged, would pass through orclosely adjacent to the above described ref` erence point D1 so that byturning the support D-7 on this pintle, the angular position of theplane of the disk D maybe adjusted with respect to theplane of the bladewithout materially varying the point of contact between the disk andtheblade.'v This adjustment may be made and maintained by means of a rodD-23, Fig. 8, secured at its upper end to a link D--24 pivoted to theunderside of the support D-7 adjacent to the belt D-5, and having itslower end passing loosely through an elongated aperture D-25 formed inan ear D-QG which projects laterally from the rear end of 'the carriageD-l3, the rod D--23 being provided at its lower end with a pairofflocklng nuts D-27 adapted to engage the upper and lower facesyrespectively of the ear D-26, whereby the rod may be adjusted withrespect to the ear D-26 and slot D--25 and locked in anyk desiredposition. n

The block D-f22 is provided with a downwardly extending circular bossD-28 which is received in a similarly shapedrecess in slide member D`29extending downwardinto a slot D--30 in the bifurcated` rear end of thecarriafgferD'-l.` The block D--22 -may be angularly adjusted' with'respect to the slide member D'-29 by` looseni'ng the bolts D-Bl whichpass through circumferential slots D-32 in the block D--22 and arethreadedY into the slide member D-`29. A bolt D-33 passes centrallythrough an aperture in the slide member D--29 and is threaded into theblock D-22, this bolt having a" washer orenlargement adapted to engagethe carriage D-13 on both sides of the slot D-30 and thus hold the slidemember D-29 in adjusted position in the slot D-30. -The purpose of theangular adjustment betweenv the vparts D-29 and D-22 is not primarilyfor use in the operation of the machine, but

rather to compensate for inaccuracies in the making or assembling of thevarious parts, so as to bring the reference point D1 exactly over theedge of the blade at their point of contact and in the desired positionrelative thereto. When the slide 'member'D-f29 is adjustedlongitudinally of thefslot D-30, the

vlwith the reference point D-l on the disk D, and therefore, also withthe spot being acted upon. The effect vof such adjustment of thecarriage is to change'the angle of the plane of the disk D with respectto a line tangent to the blade edge at the point where the. disk D bearson it, and consequently this determines the direction of the abradingaction with respect/ to the blade edge. This adjustment en once madedoes not need to be altere ,/and in practice it will suice to secure t ecarriage D--13 in a predetermined one several different angularpositions by providing the bracket D`34 with a number of threadedapertures D-35 into any one of which a clamping bolt D-36 passingthrough the carriage may be screwed.

Provision is made for automatically 'raising and lowering the disk D bymeans of a pin D-37 which passes through the carriage D-13 and iscapable of sliding vertically therein, its upper end being locateddirectly beneath a boss D38 formed on the underside of the arm D--8.`Beneath the lower end of the pin D-37 is located a pressure-operatedcylinder D-39, the upper end of which is enlarged and serves to supportthe lower end of the pin D-37 in any position of the carriage 'I3-13.The piston D--40 is provided with an enlarged base D-ll rigidly fixed tothe base A and has a perforation D-42 passing through it from end to endin line with the open end of a pipe 1)-43 passing through the base A andadapted to convey iiuid under pressure to the interior of the cylinder,the admission of the Huid to the pipe D-43 being automaticallycontrolled in any desired manner, as by the overhead mechanism abovereferred to, which may include a suitable controlling valve K28operatedl by one of the cams on the drum as explained in my prior patentabove referred to. The admission of fiuid pressure to the pipe D-43 willresult in lifting the cylinder 1)-39l and with it the pin D-ST until thelatter strikes the boss D-38, thereafter lifting the arm D8 and disk Duntil the upward movement of thel cylinder D-39 is arrested by theengage-ment of its upper end with the underside of the carriage D-13,and when the fluid pressure is relieved, the arm D-S is moved downwardby its own weight.

The blade support may be oscillated to effeet the grinding operation bymeans of a link B-22 having a universal-joint 'connection at one end toa projection B-28 extending laterally from the sleeve B-2 and at itsother end to a crank pin B-24 carried by a disk B--25 which is mountedon a counter-shaft B-26 located at the rear of the machine andjournalled in fixed brackets B-27 secured to the base A, the counterhaftB-26 being provided with a driving pulley B-28 by means of which it iscontinuously rotated from any suitable source of power.

In order to provide for varying the amplitude of the oscillations of thesleeves B-2 and f B-4, the crank pin B-24 may be adjustably secured in aradial slot B-29 in the crank disk B-Q, in which case a change in theposition of the pin B24 in the slot B-29 will change the eccentricity ofthe crank and consequently the throw of the link B-22.

The upper part of the blade support may be moved into loading andunloading position by means of a horizontal swinging arm B--3O locatedbehind the blade support and pivoted at one end to a bracket B-31secured to the base piece C-2L At its free end the arm B3O is pivoted toa curved link B-32 llaving a slot B-33 through which passes a pin B-34carried by anarm B-S which is secured to the sleeve-1B-4, and betweenits ends the arm B-3O is connected by a link B-36 to one arm ofl a bellcrank lever B--ST pivotally mounted on the base piece C2. The other armof the bell crank lever B-S is connected to a pull lrod B-SS whichextends upward to and is movable upwardly by the overhead operatingmechanism previously referred to,fagainst the tension of a coiled springB-39 which connects one arm of the bell crank lever B-37 and a point onthe baie piece 0 2.' lfVhile the blade is being operated upon, fthespring B-39 maintains the links B-BO and B--32 in the position shown inFig. 4, the slot B-l being of such length that the pin B--M can moreback and forth in it iwhile the sleeve B-l is osclllated by the rotatingcrank disk and linkage above described,*but when the pull rod B-38 ismoved upward by the overhead mechanism, the link B--Sfi is drawnbackward whereupon the link lie-32 moves freely until the front end ofthe slot B-Z reaches the pin B-34, thel sleeve B`-l then being moved tothe position shown in Fig. 5. The blade holder is then" in the loadingand unloading position, where the blade/is out of range of the action ofthe disk D. The movement takes place against the resistance of thespring B-, thus enabling the oscillations of' the sleeve B-2 to continueirrespective of the position of the sleeve-B-4. The loading andunloading position is determined by the adjustment of a suitable stop,such for example as the stop bolt 13,-40, Figs. 4 and 5, carried by thebase piece (1 2, the front endof the bolt being engaged by the arm B-when it is pulled backward.

Adjustment of the stop bolt B7 has ythe effect of changing the point onthe blade edge at which the abrading action of the disk D begins at theheel of the blade edge, the path of oscillation of the blade carrierbeing adjustable as to length or amplitude as described above exactly tocover the distance between the'v heel of the edge and its point.

The pressure of the abrading disk D on the blade may be determined by aweight consisting for example of a number of disks D-44 strung on a rodD-45 suspended on a hook D-46, Fig. 3, which is secured to the undersideof the bearing D--3 with the lower end of the rod passing downwardthrough a hole Ain the base A. By adding or subtracting disks theapplied weight can be regulated as desired.

The. construction and timing of the overhead mechanism is such thatafter the blade support moves into the loading position shown in Fig. 5,the plunger C is lifted and thereupon the holding plate B9 is swung lupward by means ofthe spring B--15. j After a blade to be sharpened hasbeen positioned" on the Aplate B-16 the plunger C `isrforced downward bymeans of the'parts C-4 and 0 3 actuated by the overhead mechanismthrough the pull rod C-G, causing the plate B-9 to clampthe blade on theblade support. The tension on the pull rod B-38 is released and it isdrawn downward Aby the spring B-BS), and the blade support moves yintothe position shown inFig. 4, the abrading disk at this time being heldout of-contact with the blade by the fiuid under pressure in thecylinder D-39. The fluid'pressureinthis cylinder is then exhausted,y,permitting the disk D to move downlinto Contact with the blade, andsince this disk rotates continually and the blade support as a whole isoscillated continually, the abradin action begins as soon as lthe disktouches the lade and con- 'tinues until the bevel lhas been sufficientlyoperated upon. Fluid pressure is then ai mitted to the cylinderD-39 bythe automatic mechanism and'lifts the disk D out of` ycontact 4with theblade, the blade 'support B-4 thenbeing swung into the loading andunloading position, Fig. 5, by the overhead@ mechanism operating throughthe pull rod B-38, the plunger C being lifted,`and the' vtop plate B-9swinging upward. The blade is then removed and replaced by'another,

whereupon the cycle ofI operations isrepeat'ed.

It remamsto describe certain. effects of' various adjustmentsprovided-for inthe con-l struction of the sharpening unit.` Theseeffects will depend to some extent upon the transverse contourv oftheperiphery ofthe' wouldconform in curvature to the disk it,

self` and on a blade ofgiven thickness the width of the bevel woulddepend upon the curvature of the disk, 'assuming the action'jV of theydisk to be limited tothe upper half of the blade. Anl increase in ithediameter of the disk would result in a rbevel of increased width andradius of curvature, anda decrease vinthe di ameterof thedisk wouldresultlin a bevel of less width and radius of curva.

ture. If the plane of the disk were tilted with respect to the plane oftheblade, with-vk out otherwise changing theirrelatlons, the

shape of the bevel would not begafi'ected, but the abrading action ofvthe disk would be confined to one vof? its corners. o

On the other hand,'if theplane of the disk were perpendicular to theplane of the blade but parallel with the direction of the blade `edgeoatthe point of contact, the disk would grind a rabbet at the edge of theblade, and in order to make it grind a bevel it would be necessary totilt theplane of the disk with respect to the-.plane of the blade.Theangle 'andiwidth ofthe bevel thus produced would dependuponthe angleof tilt, but atalnyl i angle the' bevel lwould bev flat and notconthickness .of the disk.

the blade can be varied by adjusting the arm f D-8, angularly about `theaxis ot the .pintle 'D-QO, and the angle between the disk and thedirection ofthe blade edge at the point `o f contact can be adjusted bymoving the car-` f rlage on the arc-shaped bracket D-34,both

of these adjustments being limited to a certain range'which suffices forall practical purposes, althoughthe range of movement of the carriage onthe bracket D`34= is such that the disk nevercrosses the blade edge at aright angle thereto. In any such intermediate adjustment ofthe disktilting is necessary 'to cause the whole width of thefcylindricalsurface of the disk to bear on the blade. The

position of the abrading disk transversely withk respect to the edge oftheblademay be varied by adjusting the arm D -S'with the susI slidemember D`29 longitudinally along the slot `D---BO inthe carriage D-13.It follows from'the foregoing explanation that adjustf mentsot thecarriage onthebracket D-34 serve'to varyfbothy the concavity andthewidth of `the bevel on the blade, while ;a dj ustments of the disk aboutthe axis dcterminedby the pintle D--2O serve primarily to distributethewear over the entire periphery of the disk,

some extent by the. other. In practice the adjustment `ofl-the carriageis limited to a which range it is employed chiefly, to determinel the`width of the bevel, the cha-nge in ,the-fconcavity being relativelyunimportant..` By suitably combining these adjustments alV bladebevel ofanydesired contour, within certain limits,.may be readily produced. f

small range about the arc-shaped bracket inf' It' will be observed thatthe mechanismide-v scribed -iis adapted to sharpen one bevelV only,`

and in order to sharpen thecother bevel I eml ploy.asimilarimachine'with the partsof the in position inanjobvious manner,but otherwise exactly similar to the machine described.

While the` specific apparatus above described is designed for sharpeningblades blade carrier. and. the abrading kunit reversed 1,20*

having curved ledges, it will be evident that f various features of theinvention aref'applicable to'machines forlsharpening blades hav-,6.

construction and arrangementmay be widethe result of each adjustmentbeing affted yq 105,

holder in the plane of the blade so as to bring every point of the edgeto be sharpened into contact with the abrading disk, and adjustablemeans for limiting the movement of the disk towards the blade.

2. Ina blade sharpening machine, a circular abrading disk, means foroscillating a curved blade beneath a point in the periphery of the disk,a shaft on which said disk is' p mounted, an arm adjacent to one end ofwhich'said shaft is mounted, a carriage supporting said arm, and anarcuate support having its center of curvature adjacent to the point ofcontact between the abrading disk and the blade around which center thecarriage is movable, whereby to vary the angle between the plane of theabrading disk and the blade edge at their point of Contact andconsequently to vary the width and degree of concavityof the bevel.

3. InV av machine for sharpening curvededge blades, an abrading diskadapted to be rotated with its plane at an acute angle to the blade edgeat its pointof contact, a shaft on which said disk is fixed, an armadjacent to one end of which said shaft is rotatably mounted, a supportcarrying said arm, a carriage upon which saidsupport is pivotallymounted, the axis of movement of said support being located adjacent tothe point of contact between said disk and the blade, means foradjusting the position of said support relatively to said carriage,whereby to vary the angle between the plane of the blade and the planeof the disk, and anl arc-shaped support having its center of curvatureadjacent tothe point of contact between the disk and the blade aroundwhich said carriage is adapted to be moved, whereby to vary the anglebetween the plane of the disk and the edge of the blade at the point ofcontact and consequently to vary the width and concavity of thebladebevel.

4. In aV blade sharpening machine, an abrading tool, a blade holdermounted for oscillatory movement, means for oscillating the holder, amovable blade clampingmember carried bysaid holder, and an operatingmember located outsidesaid holder and having a point bearing with saidclamping member located in alignment 'with the axis of 0sunit in apredetermined path to effect the` grinding operation, and automaticmecha- ,rrsm for extending the movement of one part only ot the unitbeyond its normal oscillation to carry the blade out of range of theabrading disk.

6. In blade shaponding machine, a rotary abrading disk, an oscillatoryblade holder comprising a base part and a blade clamping part movableabout the same axis. means connected to the base part for oscillatingthe holder as a unit, and separate mechanism connected to the bladeclamping part for oscillating that part independently of the base art.

7 In a blade sharpening machine, a rotary abrading disk, an voscillatoryblade holder for a curved edge blade, means for oscillatingfsaid holderin a predetermined path, and operating means having a lost motionconnection with said holder while it moves in its normal path arrangedto impart an additional further movement to the holder at predeterminedintervals.

8. Inl a blade sharpening machine, a rotatable blade holder including 'apivotally mounted sleeve and adjustable clamping means disposed at oneend thereof, an abradtion adjacent said clamp, means for moving loneedge of said clamping means beyond the l range of the abrading disk andcooperating means or moving said disk away from said f blade holder topermit` adjustment of said clamp.

9. In a blade sharpening machine, a power operated holder for securingarticles to be ground and movable therewith in a curved path, avertically movable arm arranged above said article, an adjustable stop`for positioning the arm in a predetermined vertical position, arotatable abrading disk at the free end of the arm and a fluid actuateddevice for raising said arm from said stop.

10. In a machine for sharpening curved blades the combination with arotary abrading disk, of a blade holder, mechanically actuated means foroscillating the holder to present every point in the edge of a curvedblade to the action of the disk, and: automatic means for periodicallyextending the movement of the holder beyond the normal lrange of itsoscillating movement to locate it in loading or unloading position.

11. Ina machine for sharpenin curved edge blades, a rotary abrading disa twopart oscillatory` blade holder cooperating therewith, poweroperated mechanism for oscillating the holder as a unit about its aXis Ito grind a blade in the holder while leaving one part of the holder freefor independent oscillation about the same axis, and means forindependently oscillatingsaid part to carry the sharpened blade beyondthe range of the abrading disk.

12. In a blade sharpening machine, a driv en abrading disk, means foroscillating a curved blade beneath the disk, a shaft carrying the disk,a pivotally mounted arm in the free end of which said shaft is mounted,a carriage supporting the arm and being bodily adjustable in an arcuatepath having as its center of curvature the point of contact of the diskwith the blade, and provision for bodily adjusting said arm and disktransversely with respect to the edge of the blade being sharpened.

Signed at Boston, Massachusetts, this twenty-third day of August, 1927.`

WILLIAM EMERY NICKERSON.

